Display control apparatus, display control method, and camera monitoring system

ABSTRACT

A display control apparatus configured to be connected to an imaging apparatus is provided. The display control apparatus includes an obtaining unit configured to obtain image data captured by the imaging apparatus by capturing an image behind a vehicle; an edge image generation unit configured to generate edge image data that clearly indicates a peripheral portion of the image data to be viewed via an electric mirror that is placed at a rear-view mirror position inside the vehicle; a display image generation unit configured to generate display image data by superimposing the generated edge image data onto the obtained image data; and a control unit configured to control the generated display image data to be viewed via the electric mirror.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a display control apparatus, a displaycontrol method, and a camera monitoring system.

2. Description of the Related Art

Conventionally, a display control technique is known in which a cameramonitoring system is installed in a vehicle, a captured image behind thevehicle is displayed by a display apparatus, or the like, and thus, thedisplay apparatus, or the like, functions as an electric mirror. In thecase where an electric mirror is compared with conventional mirrors usedfor viewing behind the vehicle (side mirror, rear-view mirror), theelectric mirror has an advantage in that, for example, a distant objectcan be viewed clearly.

CITATION LIST Patent Document

-   [Patent Document 1] Japanese Unexamined Patent Application    Publication No. 2013-003641

SUMMARY OF THE INVENTION Technical Problem

With respect to the above, in the case where an electric mirror is usedin place of the rear-view mirror as described above, there is a problemas follows. In general, different from the rear-view mirror, an electricmirror does not provide a view inside the vehicle. Therefore, for adriver, it is difficult to clearly recognize a boundary between acaptured image behind the vehicle that is viewed via the electric mirrorand the surroundings of the captured image (e.g., a front view that isviewed through a windshield). As a result, there is a possibility thatthe driver mistakenly perceives the captured image behind the vehiclethat is viewed via the electric mirror as a front view.

In view of the above problem, it is an object of the present inventionto make it easy to recognize a boundary between the image that is viewedvia the electric mirror and the surroundings of the image.

Solution to Problem

According to an aspect of one or more embodiments, a display controlapparatus that is connected to an imaging apparatus is provided. Thedisplay control apparatus includes: an obtaining unit configured toobtain image data captured by the imaging apparatus by capturing animage behind a vehicle; an edge image generation unit configured togenerate edge image data that clearly indicates a peripheral portion ofthe image data viewed via an electric mirror that is placed at arear-view mirror position inside the vehicle; a display image generationunit configured to generate display image data by superimposing thegenerated edge image data onto the obtained image data; and a controlunit configured to control the generated display image data to be viewedvia the electric mirror.

Advantageous Effects of Invention

It becomes easier to recognize a boundary between an image viewed via anelectric mirror and the surroundings of the image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing illustrating an example of a system structure of acamera monitoring system according to a first embodiment.

FIG. 2 is a drawing illustrating a placement example of a displayapparatus.

FIG. 3 is a drawing illustrating an example of a hardware structure of adisplay control apparatus.

FIG. 4 is drawing illustrating an example of a functional structure of adisplay control apparatus according to the first embodiment.

FIGS. 5A-5D are drawings illustrating display examples of the displayapparatus.

FIG. 6 is a flowchart illustrating a display control process flow of thedisplay control apparatus according to the first embodiment.

FIG. 7 is a drawing illustrating an example of a system structure of acamera monitoring system according to a second embodiment.

FIG. 8 is drawing illustrating an example of a functional structure of adisplay control apparatus according to the second embodiment.

FIGS. 9A-9D are drawings illustrating display example of the displayapparatus.

FIG. 10 is a flowchart illustrating a display control process flow ofthe display control apparatus according to the second embodiment.

FIG. 11A and FIG. 11B are drawings illustrating an example of a systemstructure of a camera monitoring system according to a third embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, one or more embodiments of the present invention willbe described while making reference to the drawings. It should be notedthat, in the present specification and the drawings, the same referencenumeral is given to an element that has substantially the samefunctional structure, and duplicated descriptions will be omitted.

First Embodiment

<System Structure of Camera Monitoring System>

First, a system structure of a camera monitoring system that isinstalled in a vehicle will be described. FIG. 1 is a drawingillustrating an example of a system structure of a camera monitoringsystem 100 according to a first embodiment. As illustrated in FIG. 1,the camera monitoring system 100 includes an imaging apparatus 110, adisplay control apparatus 120, and a display apparatus 130. It should benoted that, in one or more embodiments, it is assumed that the cameramonitoring system 100 is started when an ignition switch of the vehicleis turned ON, and is stopped when the ignition switch is turned OFF.However, the camera monitoring system 100 may be started and stoppedbased on instructions of a driver of the vehicle.

The imaging apparatus 110 captures an image of a view behind thevehicle, and transmits image data that is obtained by horizontallyflipping the captured image to the display control apparatus 120. Thedisplay control apparatus 120 superimposes data with a predeterminedcolor onto a peripheral portion of the image data transmitted from theimaging apparatus 110 by processing the image data, and transmits, asdisplay image data, the superimposed result to the display apparatus130. The display apparatus 130, an example of an output apparatus, is aliquid crystal display apparatus in one or more embodiments, anddisplays the display image data transmitted from the display controlapparatus 120.

<Placement Example of Display Apparatus>

Next, a placement example of the display apparatus 130 will bedescribed. FIG. 2 is a drawing illustrating the placement example of thedisplay apparatus 130. As illustrated in FIG. 2, the display apparatus130 is placed at a rear-view mirror position inside a vehicle (a centralposition on the near side of the windshield), and functions as anelectric mirror in place of the rear-view mirror.

<Hardware Structure of Display Control Apparatus>

Next, a hardware structure of the display apparatus 120 will bedescribed. FIG. 3 is a drawing illustrating an example of a hardwarestructure of the display control apparatus 120. As illustrated in FIG.3, the display control apparatus 120 includes a CPU (Central ProcessingUnit) 301, a ROM (Read Only Memory) 302, and a RAM (Random AccessMemory) 303. Further, the display control apparatus 120 includes a GPU(Graphic Processing Unit) 304 and an I/F (Interface) apparatus 305. Itshould be noted that the units of the display control apparatus 120 areconnected to each other via a bus 306.

The CPU 301 is a device for executing various programs (e.g., a displaycontrol program, etc.,) installed in the ROM 302. The ROM is anonvolatile memory and functions as a main memory device for storing thevarious programs executed by the CPU 301. The RAM 303 is a volatilememory such as a DRM (Dynamic Random Access Memory), an SRM (StaticRandom Access Memory), etc. The RAM 303 functions as a main memorydevice for providing a work area that is generated when the variousprograms installed in the ROM 302 are executed by the CPU 301.

The GPU 304 is an integrated circuit dedicated for executing imageprocessing, and, in one or more embodiments of the present invention,generates display image data to be displayed by the display apparatus130 based on an instruction from the CPU 301 executing the displaycontrol program. The I/F apparatus 305 is a connection device forconnecting the imaging apparatus 110 and the display apparatus 130 tothe display control apparatus 120.

<Functional Structure of Display Control Apparatus>

Next, a functional structure of the display control apparatus 120 willbe described. FIG. 4 is drawing illustrating an example of a functionalstructure of the display control apparatus 120 according to the firstembodiment. As described above, the display control program is installedin the display control apparatus 120. When the camera monitoring system100 is started, the display control apparatus 120 executes the displaycontrol program. According to the above operations, the display controlapparatus 120 functions as an image data obtaining unit 410, an edgeimage generation unit 420, a display image generation unit 430, and acontrol unit 440.

The image data obtaining unit 410 obtains image data transmitted fromthe imaging apparatus 110. The image data obtaining unit 410 transmitsthe obtained image data to the display image generation unit 430 frameby frame.

The edge image generation unit 420 generates data with predeterminedcolor that clearly indicates a peripheral portion of the image data tobe displayed by the display apparatus 130 (referred to as “edge imagedata”), and transmits the generated data to the display image generationunit 430. The edge image data, generated by the edge image generationunit 420, is, for example, data that is used for causing the entireperipheral portion of the image data to be white. However, the edgeimage data generated by the edge image generation unit 420 is notlimited to the above. For example, the position at which the data withthe predetermined color is placed is not limited the entire peripheralportion of the image data, and may be only corner portions of theperipheral portion. Alternatively, the position may be three sides (or,one side, two sides) of the four sides of the peripheral portion.Further, it is not necessary for the data with the predetermined colorto be placed in a solid strip shape. The data with the predeterminedcolor may be placed in a dotted strip shape.

Further, the predetermined color to be placed is not limited to white,but may be a different predetermined color, or may be selected from aplurality of colors. In this case, the selection of colors to be placedmay be performed automatically, or may be performed based on aninstruction of a driver. In any case, it is assumed that the edge imagedata should be generated in a display format (or, display manner,display style) that causes, when the display image data is displayed bythe display apparatus 130, the boundary between the display image dataand a front view to be clearly recognized.

The display image generation unit 430 generates display image data bysuperimposing the edge image data generated by the edge image generationunit 420 onto each frame of the image data transmitted from the imagedata obtaining unit 410, and transmits the generated display image datato the control unit 440. The control unit 440 controls the display imagedata transmitted from the display image generation unit 430 to bedisplayed by the display apparatus 130. With the above operations, it ispossible for the driver of the vehicle to recognize the display imagedata via the display apparatus 130.

<Display Example of Display Apparatus>

Next, a display example of the display apparatus 130 will be described.FIGS. 5A-5D are drawings illustrating display examples of the displayapparatus 130. It should be noted that, in each example in FIGS. 5A-5D,both the display image data recognized by the driver of the vehicle viathe display apparatus 130 and a front view recognized by the driverthrough the windshield that is behind the display apparatus 130.

Of all examples in FIGS. 5A-5D, FIGS. 5A and 5C are provided forcomparison and illustrate display examples of a case in which thedisplay image data, onto which the edge image data is not superimposed,is displayed by the display apparatus 130. On the other hand, FIGS. 5Band 5D illustrate display examples of a case in which the display imagedata, onto which the edge image data is superimposed, is displayed bythe display apparatus 130.

As illustrated in FIG. 5A, it is assumed that a rear surface of an aheadvehicle (a vehicle traveling ahead) 501, viewed through the windshield,is located adjacent to a front surface of a behind vehicle (a vehicletraveling behind) 502, viewed via the display apparatus 130. Asdescribed above, a view inside the vehicle is not provided by thedisplay apparatus 130, and thus, the boundary between the rear surfaceof the ahead vehicle 501 and the front surface of the behind vehicle 502is only an outer frame 510 of the display apparatus 130. Therefore, inthe case of the display image data onto which no edge image data hasbeen superimposed, it is difficult for a driver of the vehicle torecognize the boundary between the front view viewed through thewindshield and the display image data viewed via the display apparatus130. As a result, there is a possibility that the driver mistakenlyperceives the display image data viewed via the display apparatus 130 asa front view.

On the other hand, FIG. 5B illustrates an example in which the displayimage data, onto which the edge image data 520 has been superimposed, isdisplayed by the display apparatus 130. As illustrated in FIG. 58,because the edge image data 520 has been superimposed, the boundarybetween the rear surface of the ahead vehicle 501 and the front surfaceof the behind vehicle 502 includes the outer frame 510 of the displayapparatus 130 and the edge image data 520. In other words, bysuperimposing the edge image data, it becomes easier for a driver of thevehicle to recognize the boundary between the front view viewed throughthe windshield and the display image data displayed by the displayapparatus 130. As a result, it is possible to reduce the possibility ofthe driver mistakenly perceiving the display image data viewed via thedisplay apparatus 130 as a front view.

FIG. 5C illustrates a similar situation as FIG. 5A reproduced for thenight time. In case of the night time, when compared with a case of theday time (a case of FIG. 5A), it becomes difficult to recognize theouter frame 510 of the display apparatus 130, and thus, the possibilityof the driver mistakenly perceiving display image data viewed via thedisplay apparatus 130 as a front view increases.

With respect to the above, as illustrated in FIG. 5D, by superimposingthe edge image data, the boundary between taillights of the aheadvehicle 501 and headlights of the behind vehicle 502 includes the edgeimage data 520. In other words, by superimposing the edge image data, inthe case of night time, it becomes easier for a driver of the vehicle torecognize the boundary between the front view viewed through thewindshield and the display image data displayed by the display apparatus130. As a result, it is possible to reduce the possibility of the drivermistakenly perceiving the display image data viewed via the displayapparatus 130 as a front view.

It should be noted that, compared with a case of causing the outer frame510 of the display apparatus 130 itself to be easier to be recognized(e.g., embedding an LED, or the like, into the outer frame 510, andturning ON the embedded LED), a camera monitoring system 100 accordingto an embodiment of the present invention has an advantage in that thesimilar effects can be realized with lower cost.

<Flow of Display Control Process>

Next, a process flow of a display control performed by the displaycontrol apparatus 120 will be described. FIG. 6 is a flowchartillustrating a display control process flow of the display controlapparatus 120 according to the first embodiment. When the cameramonitoring system 100 is started, the display control apparatus 120performs a display control process illustrated in FIG. 6.

In step S601, the image data obtaining unit 410 obtains image data fromthe imaging apparatus 110, and transmits the image data to the displayimage generation unit 430 frame by frame. In step S602, the edge imagegeneration unit 420 generates edge image data and transmits thegenerated edge image data to the display image generation unit 430.

In step S603, the display image generation unit 430 generates displayimage data by superimposing the edge image data transmitted from theedge image generation unit 420 onto the image data transmitted from theimage data obtaining unit 410, and transmits the generated display imagedata to the control unit 440. In step S604, the control unit 440controls the display image data to be displayed by the display apparatus130 frame by frame.

In step S605, the image data obtaining unit 410 determines whether thedisplay control process should be finished. In the case where theoperation of the camera monitoring system 100 should be continued, it isdetermined that the display control process should not be finished instep S605 (in case of “No” in step S605), and the flow returns to stepS601. On the other hand, in the case where the operation of the cameramonitoring system 100 should be stopped (in case of “Yes” in step S605),the display control process is ended.

SUMMARY

As clearly described in the above, a display control apparatus 120according to an embodiment of the present invention:

generates display image data by superimposing the edge image data ontoimage data obtained by horizontally flipping an image captured by theimaging apparatus 110 used for capturing an image of a view behind thevehicle, and

displays the generated display image data on the display apparatus 130that is placed at a rear-view mirror position inside the vehicle, andthat functions as an electric mirror.

With the above operations, the display apparatus 130 displays an imagein which the peripheral portion has been clearly indicated, and thus, itbecomes easier to recognize the boundary between the image viewed viathe display apparatus 130 and the front view viewed through thewindshield (that is, the boundary between the image and the surroundingsof the image).

Second Embodiment

In the first embodiment, it is described that the edge image data isgenerated for making it easier to recognize the boundary between theimage viewed via the display apparatus 130 and the front view viewedthrough the windshield. With respect to the above, in a secondembodiment, a portion of the edge image data generated for making iteasier to recognize the boundary is used for reporting, to the driver ofvehicle, information received from an in-vehicle network. In thefollowing, the second embodiment will be described by mainly describinga difference from the first embodiment.

<System Structure of Camera Monitoring System>

FIG. 7 is a drawing illustrating an example of a system structure of acamera monitoring system 700 according to a second embodiment. Thecamera monitoring system 700 illustrated in FIG. 7 differs from thecamera monitoring system 100 in FIG. 1 in that the display controlapparatus 120 is connected to an in-vehicle network 710, and thatvehicle information is received from the in-vehicle network 710.

The in-vehicle network 710 is a network mounted on the vehicle, andcommunications are performed based on standards such as CAN (ControllerArea Network), Flexray, etc. In the present embodiment, the displaycontrol apparatus 120 is connected to the in-vehicle network 710, andthus, the display control apparatus 120 receives, as the vehicleinformation, data indicating a distance to an obstacle behind thevehicle and a direction of the obstacle. It should be noted that it isassumed that the data, indicating a distance to an obstacle behind thevehicle and a direction of the obstacle, is generated based on, forexample, a received signal from a radar sensor, a sonar sensor, or thelike, installed in the rear of the vehicle, and the data can be receivedvia the in-vehicle network 710.

<Functional Structure of Display Control Apparatus>

Next, a functional structure of a display control apparatus 120according to the second embodiment will be described. FIG. 8 is drawingillustrating an example of a functional structure of the display controlapparatus 120 according to the second embodiment. Differences betweenthe functional structures in FIG. 8 and FIG. 4 include an approachingobstacle detection unit 800 and an edge image generation unit 810.

The approaching obstacle detection unit 800 detects an obstacleapproaching with a speed equal to or greater than a predetermined speedby receiving vehicle information from the in-vehicle network 710 and bymonitoring a distance to the obstacle behind the vehicle. Further, inthe case where an object, approaching with a speed equal to or greaterthan the predetermined speed, is detected, the approaching obstacledetection unit 800 transmits, as approaching obstacle information, thedistance to the obstacle and the direction of the obstacle to the edgeimage generation unit 810.

Upon receiving the approaching obstacle information from the approachingobstacle detection unit 800, the edge image generation unit 810identifies a position of the obstacle on the image data based on thedirection and the distance of the approaching obstacle. Further, whengenerating the edge image data, the edge image generation unit 810causes the color of a portion corresponding to the identified positionto be different (e.g., red) from the color of other portions, andtransmits the edge image data to the display image generation unit 430.

<Display Example of Display Apparatus>

Next, a display example of the display apparatus 130 will be described.FIGS. 9A-9D are drawings illustrating display examples of the displayapparatus 130. Of the display examples, examples in FIGS. 9A and 9Cillustrate a state prior to a state in which an obstacle (a behindvehicle 502) approaches with a speed equal to or greater than apredetermined speed, and examples in FIGS. 9B and 9D illustrate a statein which the obstacle (the behind vehicle 502) has approached with aspeed equal to or greater than the predetermined speed.

As illustrated in FIGS. 9A and 9C, the edge image data 520 has a uniformcolor in a state in which the behind vehicle 502 has not yet approachedwith a speed equal to or greater than the predetermined speed. On theother hand, as illustrated in FIGS. 9B and 9D, in a state in which thebehind vehicle 502 has approached with a speed equal to or greater thanthe predetermined speed, the color of a portion 901 corresponding to aposition, of the behind vehicle 502 on the image data, identified basedon the direction and the distance of the behind vehicle 502, is changedto a color different from the color of the other portions. With theabove operations, it is possible for the driver to recognize that thebehind vehicle 502 is approaching with a speed equal to or greater thanthe predetermined speed via the display apparatus 130.

<Flow of Display Control Process>

Next, a process flow of display control performed by the display controlapparatus 120 will be described. FIG. 10 is a flowchart illustrating adisplay control process flow of the display control apparatus 120according to the second embodiment. Differences between the flowchartsin FIG. 10 and FIG. 6 include steps S1001 to S1006.

In step S1001, the approaching obstacle detection unit 800 receivesvehicle information from the in-vehicle network 710 and identifies adistance to an obstacle behind the vehicle. In step S1002, theapproaching obstacle detection unit 800 compares a distance to theobstacle behind the vehicle identified at the timing of obtaining theimage data with respect to a predetermined previous number of frames,with a distance to the obstacle behind the vehicle identified in stepS1001.

In step S1003, the approaching obstacle detection unit 800 detects anobstacle behind the vehicle approaching with a speed equal to or greaterthan a predetermined speed by monitoring a change, per unit time, of thedistance to the obstacle behind the vehicle. In step S1003, in the casewhere an obstacle behind the vehicle approaching with a speed equal toor greater than the predetermined speed is detected (in case of “Yes” instep S1003), the flow moves to step S1004.

In step S1004, the approaching obstacle detection unit 800 transmits, asapproaching obstacle information, the distance to the obstacle and thedirection of the obstacle to the edge image generation unit 810. Theedge image generation unit 810 identifies a position of the obstacle onthe image data based on the transmitted approaching obstacleinformation.

In step S1005, the edge image generation unit 810 generates edge imagedata in which a portion, of a peripheral portion of the image datadisplayed by the display apparatus 130, corresponding to the identifiedposition is caused to have a first color (e.g., red) and the remainingportion is caused to have a second color (e.g., white).

On the other hand, in step S1003, in the case where an obstacle behindthe vehicle approaching with a speed equal to or greater than thepredetermined speed is not detected (in case of “No” in step S1003), theflow moves to step S1006. In step S1006, the edge image generation unit810 generates edge image data in which the entire peripheral portion ofthe image data displayed by the display apparatus 130 is caused to havea second color (e.g., white).

SUMMARY

As clearly described in the above, a display control apparatus 120according to an embodiment of the present invention:

receives, as vehicle information, data indicating a distance to anobstacle behind the vehicle and a direction of the obstacle, and detectsan obstacle behind the vehicle approaching with a speed equal to orgreater than a predetermined speed, and

, in the case where an obstacle behind the vehicle approaching with aspeed equal to or greater than the predetermined speed is detected,identifies a position of the obstacle on the image data based on thedistance to the obstacle and the direction of the obstacle, andgenerates edge image data in which the color of a portion correspondingto the identified position is different from the color of the otherportions.

As described above, by using a portion of the edge image data, accordingto an embodiment of the present invention, it is possible for the driverto recognize an obstacle behind the vehicle approaching with a speedequal to or greater than the predetermined speed via the displayapparatus.

Third Embodiment

In the first embodiment and the second embodiment, a camera monitoringsystem 100 has been described in which the display apparatus 130 isplaced at a rear-view mirror position inside the vehicle, and thedisplay apparatus 130 functions as an electric mirror. However, thecamera monitoring system is not limited to the above. For example, aprojection mirror may be placed at a rear-view mirror position insidethe vehicle, and the projection mirror may function as an electricmirror by projecting display image data onto the projection mirror via aprojector.

FIGS. 11A and 11B are drawings illustrating an example of a systemstructure of a camera monitoring system 1100 according to a thirdembodiment. The camera monitoring system 1100 illustrated in FIG. 11Adiffers from the camera monitoring system 700 in FIG. 7 in that aprojector (image projection apparatus) 1110 is provided, in place of thedisplay apparatus 130, as an output apparatus. It should be noted that,in case of the camera monitoring system 1100, the display image data isprojected onto the projection mirror and the display image data isoptically flipped in a horizontal direction, and thus, it is notnecessary for the imaging apparatus 110 to flip the captured image in ahorizontal direction. Therefore, the display image data transmitted fromthe display control apparatus 120 to the projector 1110 is data in whichthe edge image data is superimposed onto the image data as obtained,without the captured image having been flipped in a horizontaldirection.

FIG. 11B is a drawing illustrating a relationship between the projector1110 and a projection mirror 1120. In an embodiment of the presentinvention, it is assumed that the projector 1110 is placed inside thevehicle at the ceiling part. As illustrated in FIG. 11B, the displayimage data, transmitted from the projector 1110 placed at the ceilingpart, is projected onto the projection mirror 1120 placed at a rear-viewmirror position inside the vehicle. With the above operations, it ispossible for a driver of the vehicle to recognize the display image datavia the projection mirror 1120. It should be noted that the displayimage data transmitted from the projector 1110 is projected onto apartial area of the projection mirror 1120. Therefore, in this case, byclearly indicating the peripheral portion of the image, it becomeseasier for the driver to recognize the boundary between an area in whichan image is viewed via the projection mirror 1120 and an area in whichthe image is not viewed (that is, the boundary between the image and thesurroundings of the image).

Other Embodiments

In the first to third embodiments, cases have been described in whichthe entire captured image, captured by the imaging apparatus 110, isused for generating the image data. However, the image data may begenerated by using a part of the captured image. In this case, forexample, an area used for the image data may be specified by the driver.

Further, in the first and the second embodiments, the image data, inwhich the captured image has been flipped horizontally by the imagingapparatus 110, has been transmitted to the display control apparatus120. However, the process of flipping the captured image in a horizontaldirection may be performed by the display control apparatus 120.

Further, in the first and the second embodiments, it is assumed that thedisplay apparatus 130 is placed at a rear-view mirror position insidethe vehicle. However, the structure of the camera monitoring system isnot limited to the above. For example, a display apparatus, to whosefront surface a movable semi-transparent mirror (half mirror) isattached, may be placed at a rear-view mirror position inside thevehicle. In this case, when a mode for displaying the display image datais turned ON, the display apparatus starts displaying the display imagedata, and, when the mode is turned OFF, the display apparatus stopsdisplaying the display image data. During this period (while the mode isON), the driver monitors behind the vehicle via the display image datadisplayed by the display apparatus.

With respect to the above, if the mode for displaying the display imagedata is turned OFF, then, a mode in which the semi-transparent mirrorfunctions as a rear-view mirror is turned ON, and the semi-transparentmirror moves to a predetermined position. In this case, the drivermonitors behind the vehicle via the semi-transparent mirror. However,even when the mode in which the semi-transparent mirror functions as arear-view mirror is ON, the edge image data may be displayed in the casewhere an obstacle behind the vehicle, approaching with a speed equal toor greater than a predetermined speed, is detected. In other words, evenwhen the mode for displaying the display image data is OFF, the edgeimage data may be displayed in the case where predetermined informationis detected from the vehicle information.

Further, in the first embodiment, a case of automatic color selection ofthe edge image data has not been particularly described in detail. Forexample, the color selection (or, the display format selection) may beperformed automatically according to the vehicle information.Specifically, information related to the brightness around the vehiclemay be obtained as the vehicle information, and the display format of apart or all of the edge image data may be changed according to theobtained information related to the brightness around the vehicle. Withthe above operations, for example, it becomes possible to change thedisplay format to make it easier for the driver to monitor the displayaccording to whether it is, for example, daytime hours, nighttime hours,a cloudy day, or, a fine day. It should be noted that the informationrelated to the brightness around the vehicle may be, for example,information generated based on a signal received from an illuminancesensor, or information generated based on an ON/OFF signal of headlightsof the vehicle.

Further, in the second embodiment, the edge image data is generated inwhich the color of a portion, corresponding to a position of theobstacle on the image data approaching with a speed equal to or greaterthan the predetermined speed, is caused to be different from the colorof the other portions. However, the display format of the portion,corresponding to the position of the obstacle on the image dataapproaching with a speed equal to or greater than the predeterminedspeed, is not limited to the above. For example, the portion,corresponding to the position of the obstacle on the image data, may becaused to blink, by generating the edge image data so as to display thesame color as the other portions at a predetermined period.

Further, in the second embodiment, the display format of a part of theedge image data is changed by using data, of vehicle informationreceived from the in-vehicle network 710, indicating the distance to theobstacle behind the vehicle and the direction of the obstacle. In otherwords, in the second embodiment, a part of the edge image data is usedfor reporting, to the driver, an existence of an obstacle approachingwith a speed equal to or greater than the predetermined speed. However,the use of the edge image data is not limited to the above. The displayformat of a part or all of the edge image data may be changed in thecase where another information that should be reported is detected fromthe vehicle information.

For example, in the case where information related to the gear of thevehicle is used as the vehicle information, the display format of theentire edge image data may be changed according to whether the gear isshifted to D (Drive) by the driver, or, the gear is shifted to R(Reverse). With the above operations, it is possible for the driver torecognize the state of the gear of the vehicle via the electric mirror.

Further, in the second embodiment, the approaching obstacle detectionunit 800 detects an obstacle behind the vehicle approaching with a speedequal to or greater than the predetermined speed, by receiving dataindicating the distance to the obstacle behind the vehicle and thedirection of the obstacle from the in-vehicle network 710. However, theapproaching obstacle detection unit 800 may detect an obstacle behindthe vehicle approaching with a speed equal to or greater than thepredetermined speed, by receiving the image data obtained by the imagedata obtaining unit 410. In this case, it is assumed that theapproaching obstacle detection unit 800 detects an obstacle behind thevehicle approaching with a speed equal to or greater than thepredetermined speed, by, for example, calculating the enlarging rate ofthe obstacle included in the image data between predetermined frames.

It should be noted that the present invention is not limited to theembodiments described above, and may be combined with other elements.Various modifications may be possible without departing from the spiritof the present invention.

The present application is based on and claims the benefit of priorityof Japanese Priority Application No. 2017-079772 filed on Apr. 13, 2017,the entire contents of which are hereby incorporated herein byreference.

What is claimed is:
 1. A display control apparatus configured to beconnected to an imaging apparatus, the display control apparatuscomprising: a memory; and a processor coupled to the memory, wherein theprocessor obtains image data captured by the imaging apparatus bycapturing an image behind a vehicle, generates edge image data thatindicates a peripheral portion of the image data to be viewed via anelectric mirror that is placed at a rear-view mirror position inside thevehicle, generates display image data by superimposing the generatededge image data onto the obtained image data, and controls the generateddisplay image data to be viewed via the electric mirror, wherein theedge image data indicates a boundary between a front view and thedisplay image data, and wherein the processor detects an obstacleapproaching from behind the vehicle with a speed equal to or greaterthan a predetermined speed, and controls only the generated edge imagedata that indicates the peripheral portion to be viewed via the electricmirror without having the display image data displayed in a case wherecontrolling for the display image data is stopped, but the obstacle isdetected by the processor.
 2. The display control apparatus according toclaim 1, wherein the processor generates the edge image data with adisplay format corresponding to vehicle information.
 3. The displaycontrol apparatus according to claim 1, wherein the processor generatesthe edge image data by changing a part or all of a display format of theperipheral portion in a case where predetermined information requiring areport has been detected from vehicle information.
 4. The displaycontrol apparatus according to claim 1, wherein the processor identifiesa position, of the obstacle detected by the processor, on the imagedata, and generates the edge image data in such a way that a displayformat of a portion, of the peripheral portion, corresponding to theidentified position is different from the display format of the otherportions.
 5. A display control method of a display control apparatus,the display control method comprising: obtaining image data obtained bycapturing a view behind a vehicle; generating edge image data thatclearly indicates a peripheral portion of the image data to be viewedvia an electric mirror that is placed at a rear-view mirror positioninside the vehicle; generating display image data by superimposing thegenerated edge image data onto the obtained image data; and controllingthe generated display image data to be viewed via the electric mirror,wherein the edge image data indicates a boundary between a front viewand the display image data, and wherein the display control methodfurther comprising detecting an obstacle approaching from behind thevehicle with a speed equal to or greater than a predetermined speed, andcontrolling only the generated edge image data that indicates theperipheral portion to be viewed via the electric mirror without havingthe display image data displayed in a case where controlling for thedisplay image data is stopped, but the obstacle is detected by theprocessor.
 6. A camera monitoring system comprising: an imagingapparatus configured to capture an image behind a vehicle; a displaycontrol apparatus configured to process image data captured by theimaging apparatus; and an output apparatus connected to the displaycontrol apparatus, wherein the display control apparatus includes amemory and a processor coupled to the memory, wherein the processorobtains image data captured by the imaging apparatus by capturing animage behind a vehicle, generates edge image data that clearly indicatesa peripheral portion of the image data to be viewed via an electricmirror that is placed at a rear-view mirror position inside the vehicle,generates display image data by superimposing the generated edge imagedata onto the obtained image data, and controls the output apparatus insuch a way that the generated display image data is viewed via theelectric mirror, wherein the edge image data indicates a boundarybetween a front view and the display image data, and wherein theprocessor detects an obstacle approaching from behind the vehicle with aspeed equal to or greater than a predetermined speed, and controls onlythe generated edge image data that indicates the peripheral portion tobe viewed via the electric mirror without having the display image datadisplayed in a case where controlling for the display image data isstopped, but the obstacle is detected by the processor.